docs: def get_config():
      """Get the configuration from file"""
      if CONFIG_FILE is not None:
          configfile = CONFIG_FILE
      else:
          configfile = BUILTIN_CONFIG_FILE
  
      config = {}
      with open(configfile, 'r') as fp_:
          config = recursive_dict_update(config, yaml.load(fp_, Loader=UnsafeLoader))
  
      app_dirs = AppDirs('pyspectral', 'pytroll')
      user_datadir = app_dirs.user_data_dir
      config['rsr_dir'] = expanduser(config.get('rsr_dir', user_datadir))
      config['rayleigh_dir'] = expanduser(config.get('rayleigh_dir', user_datadir))
  
      return config